A thick lava flow has been creeping down the eastern slopes of Kizimen Volcano since its eruption began in December 2010. The flow has advanced about 600 meters (2,000 feet) since September 2011.

Unlike the fluid lava commonly found on Hawaii’s Kilauea, Kizimen’s lava is extremely viscous and virtually solid. This type of “blocky” flow advances as chunks of hardened lava tumble from the front of the flow. The falling blocks expose the hot interior of the flow, visible as red (relatively cool), orange, and yellow (relatively hot) pixels in this satellite image. Dark debris—material that has fallen from the surface of the lava flow—blankets the entire eastern side of the volcano. It is fresh enough to remain uncovered by snow, despite the ongoing Russian winter. Downwind of the volcano, ash on top of snow is lighter brown.